Ruby » Ruby master

fileutils.rb: do not make root

• lib/fileutils.rb (FileUtils#mkdir_p): no need to make root
  directory which should be exist and cannot be made with mkdir
  recent Cygwin can make a directory contains a colon.
  [Bug #13214]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@57640 b2dd03c8-39d4-4d8f-98ff-823fe69b080e